Data transmission method and apparatus

ABSTRACT

A data transmission method and apparatus for performing a data transmission between end terminals of a telecommunication network, where the data is transmitted from at least one of the end terminals using the first data bearer. Then, data transmission is switched from the first to the second data bearer, if a predetermined bearer need condition has been determined or in order to obtain a subscriber identity used for gathering charging data. The network service provided by the operator can be improved, since the bearer switching allows an increase of the overall speed of the data transmission, an adaptation of the bearer bandwidth to the data amount, and a provision of the subscriber identity. The first data bearer may be a USSD or SMS data bearer, and the second data bearer may be a circuit-switched data bearer or a GPRS bearer, or vice versa.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International ApplicationPCT/EP99/09416 having an International Filing Date of 2 Dec. 1999 andfrom which priority is claimed under all applicable sections of Title 35of the United States Code including, but not limited to, Sections 120,363 and 365(c).

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for performing adata transmission between end terminals of a telecommunication network,such as a data transmission between a client and an origin server via acellular network.

BACKGROUND OF THE INVENTION

In the next few years, multimedia applications will in full scale enterthe world of cellular communications. To support new services, whichwill set new demands on the infrastructure for radio communications, anew wireless communication system needs to be developed. To meet thesedemands of wireless mobile communication in a true multimediaenvironment, high speed packed data and Internet bearer services playmajor roles.

The future of mobile telephony is now being determined by the globalstandardization work conducted by public authorities and the industry.Wireless Application Environment (WAE) is a result of the WirelessApplication Protocol (WAP) efforts to promote industry-wide standardsand specifications for developing applications and services that operateover wireless communication networks. WAE specifies an applicationframework for wireless devices such as mobile telephones, pagers andPDAs (Personal Digital Assistants). The framework extends and leveragesother WAP technologies, including Wireless Transaction Protocol (WTP)and Wireless Session Protocol (WSP), as well as other Internettechnologies such as scripting and various content formats. The effortis aimed at enabling operators, manufacturers and content developers tomeet the challenges of implementing advanced differentiating servicesand applications in a fast and flexible manner.

WAE adopts a model that closely follows the WWW (World Wide Web) model.All content is specified in formats that are similar to the standardInternet formats. The content is transported using standard protocols inthe WWW domain and an optimized protocol similar to HTTP (Hyper TextTransfer Protocol) in the wireless domain. The WAE architecture allowsall content and services to be hosted on standard Web origin servers.All content is located using WWW standard URLs (Uniform ResourceLocators).

WAE enhances some of the WWW standards in ways that reflect the deviceand network characteristics. WAE extensions are added to support MobileNetwork Services such as Call Control and Messaging. Careful attentionis paid to the memory and CPU processing constraints that are found inmobile terminals. Support for low bandwidth and high latency networks isincluded in the architecture as well.

WAE assumes the existence of a gateway functionality responsible forencoding and decoding data transferred from and to the mobile client.The purpose of encoding content delivered to the client is to minimizethe size of data sent to the client over-the-air as well as to minimizethe computational energy required by the client to process that data.The gateway functionality can be added to origin servers or placed indedicated gateways.

In the mobile stations of the mobile network, a software or device,called user agent, is provided that interprets a network contentreferenced by a URL. This may include textural browsers, voice browsers,search engines and the like.

The user agent is connected to the mobile network using dedicatedsignaling connections. The origin server communicates with the clientusing the WAP protocol stack, may be connected to the mobile network andis responsible for deploying content to its clients. In the case ofcall-handling, for example, the mobile network sets up the call to theclient, the server delivers the event-handling content, and the useragent invokes the event-handler content and manages the presentation ofthe call-handling service to the user.

However, in case a circuit switched data bearer (CSD bearer) is used fortransmitting data between the server and the mobile client, the callset-up time is relatively high, eg. 15-60 s depending on the solution.Thus, the end user has to wait for the connection and cannot use itsmobile phone.

Moreover, the user agent may have a very rigid and real-time contextmanagement. For example, the user agent may drop outdated (or stale)events, may not place intermediate results on the history stack, and maytypically terminate after the event is handled. Hence, the success ofcontent delivery (eg. handling of call control) is, to some extent,dependent on the operator's ability to access and control the speed ofthe mobile network.

Furthermore, when a mobile terminal communicates over an IP bearer byusing e.g. CSD or GPRS (General Packet Radio Service) with an externalgateway such as a WAP gateway, the MSISDN of the mobile terminal is notknown by the gateway. Therefore, the operator may only charge the userfor the used airtime (e.g. in case of a CSD connection) or for the sentdata packets (e.g. in case of GPRS connection). However, a charging perused service is not possible, since the required IP address is usuallyallocated dynamically by an access server (e.g. in case of the CSDconnection) or by an SGSN (Serving GPRS Support Node). Hence, anassociation between the MSISDN and the IP address is not available.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a datatransmission method and apparatus for improving the network serviceprovided by the operator in a data transmission between an origin serverand a mobile client.

This object is achieved by a method for performing a data transmissionbetween end terminals of a telecommunication network, comprising:

initiating the data transmission from at least one of the end terminalsusing a first data bearer; and

switching the data transmission to a second data bearer, when apredetermined bearer need condition of the second data bearer has beendetermined.

Additionally, the above object is achieved by an apparatus forperforming a data transmission between end terminals of atelecommunication network, comprising:

switching control means (e.g. a bearer switch control) for controlling atransmission means (e.g. a transmitter of a transceiver) so as toinitiate said data transmission from at least one of said end terminalsusing a first data bearer; and

detecting means (e.g. a detector) for detecting a predetermined bearerneed condition;

wherein said switching control means is arranged to control saidtransmission means so as to switch to said second data bearer inresponse to the detection result of said detection means.

Accordingly, end users can be released from the duty of selecting asuitable data bearer, and the operator is able to control the databearers used. Alternatively, WAP applications can tell the WAP gatewaythe best data bearer from their point of view. Hence, a control can beachieved in such a manner that long-term WAP sessions load trafficchannels instead of control channels.

The predetermined bearer need condition may be the completion of aset-up phase of the second data bearer. Then, an additional or auxiliarydata bearer without a call set-up time may temporarily be used insteadof the main data bearer during the period when the main data bearer isbeing established. Thereby, the delivery time of the content can bereduced, since a part of the content may already be transmitted usingthe first data bearer during the set-up phase of the second data bearer.

Thus, the network service is improved, since the WAP session startsimmediately without a call set-up time, while the transmission capacityis optimized.

Furthermore, the bearer need condition may be determined on the basis ofthe amount of data to be transmitted. The amount of data may bedetermined e.g. from a service address, a content size and/or a contenttype of a service information to be transmitted. Thereby, an initialbearer can be changed to a bearer having a narrower bandwidth, if thereis not so much content to be retrieved. Hence, network load can bereduced and service improved.

Preferably, the first data bearer is a USSD (Unstructured SupplementaryService Data) bearer or an SMS (Short Message Service) bearer, and thesecond data bearer is a circuit-switched data bearer or a GPRS bearer.Thus, the user agent may start content retrieval using the USSD or SMSbearer so as to provide a fast service delivery, wherein thecircuit-switched data bearer is used after the set-up thereof.

Alternatively, the first data bearer may be a circuit-switched databearer, and the second data bearer a USSD (Unstructured SupplementaryService Data) bearer or an SMS (Short Message Service) bearer, tothereby switch to a narrow bandwidth bearer if only a little amount ofdata is to be transmitted.

The data transmission may be used for a browsing operation between anorigin server and a mobile client, i.e. a retrieving operation forretrieving a WAP content from an origin server. In this case, anIN-numbered translation can be used to determine the number of an INaccess server. In particular, the numbered translation may be determinedby a CAMEL (Customized Applications for Mobile Network Enhanced Logic)support. The IN access server may be a WAP gateway. Accordingly, auniversal IN number can be used for addressing the WAP gateway or theorigin server.

Preferably, the switching operation may be performed during thedownloading of a specific content entity using the first bearer, so thatthe remaining content is swapped to the second bearer. Thus, a transportprotocol mechanism for using multiple bearers in parallel could beimplemented.

Furthermore, the second data bearer may be changed to the first databearer in dependence on the amount of data to be transmitted. Thereby,the main second data bearer could be changed back to the subsidiaryfirst data bearer if there is not very much content to be downloaded.

Furthermore, the switching step may comprise a WAP session suspend andresume operation, wherein a WAP session is suspended via the first databearer and resumed via the second data bearer. Thus, the presentinvention can be easily implemented by using existing WAP sessionprotocol features.

The switching control means may be arranged to control the transmittingmeans so as to switch to the second data bearer during a downloading ofa specific content entity from an origin server to a mobile stationusing the first data bearer, so that the remaining content is swapped tothe second data bearer.

Furthermore, the switching control means may be controlled by aninformation transmitted from a user agent means provided in the mobilestation. Thus, the user agent means starts content retrieval using thefirst data bearer by transmitting a corresponding information to theswitching control means of the data transmission apparatus. When thedata transmission apparatus gets informed either from the origin serveror from the mobile station that the second bearer set-up is complete,the data transmission apparatus starts using the second bearer.

In particular, the data transmission apparatus may be a WAP gateway,wherein the switching control means is arranged to perform the switchingoperation by using a WAP session suspend and resume operation.

Alternatively, the data transmission apparatus may be provided in anorigin server.

Furthermore, the above object is achieved by a method for performing adata transmission between end terminals of a telecommunication network,said method comprising the steps of:

initiating said data transmission from at least one of said endterminals using a first data bearer;

switching said data transmission to a second data bearer; and

using a subscriber identity, obtained from the data transmission withsaid first data bearer, for gathering subscriber charging data.

Additionally, the above object is achieved by an apparatus forperforming a data transmission between end terminals of atelecommunication network, said apparatus comprising:

switching control means for controlling a transmission means so as toinitiate said data transmission from at least one of said end terminalsusing a first data bearer; and

detecting means for detecting a subscriber identity from the datatransmission with said first data bearer;

wherein said switching control means is arranged to gather subscribercharging data by using said detected subscriber identity.

Accordingly, a cheap and reliable service-specific charging function canbe established, which does not require any additional network elementsfor providing the subscriber identity and/or IP address of a requestedservice. Moreover, roaming of the user does not cause any problems,since the subscriber identity is derived from the data bearer. Thus, thenetwork service provided by the operator can be improved.

Preferably, the first data bearer is a USSD (Unstructured SupplementaryService Data) bearer or an SMS (Short Message Service) bearer, and thesecond data bearer is a circuit-switched data bearer or a GPRS bearer.Thereby, the MSISDN can be obtained from the USSD or SMS bearer.

Furthermore, the above object may be achieved by a terminal equipmentfor a telecommunication network, comprising:

input means for activating a browser function; and

browser means responsive to the input means, for starting a contentretrieval from an origin server by using a first and a second databearer, wherein said content retrieval is performed by using said firstdata bearer during the set-up of said second data bearer.

Preferably, the terminal equipment is provided in a mobile terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the present invention will be described in greaterdetail on the basis of a preferred embodiment with reference to theaccompanying drawings, in which:

FIG. 1 shows a basic block diagram of a mobile network connected via agateway to an origin server,

FIG. 2 shows a basic block diagram of a data transmission apparatusaccording to the preferred embodiment of the present invention,

FIG. 3 shows an information flow diagram of two examples of a datatransmission method comprising a bearer change procedure according tothe preferred embodiment of the present invention, and

FIG. 4 shows an information flow diagram of another example of a datatransmission method comprising a bearer change procedure according tothe preferred embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following, the preferred embodiment of the present invention willbe described on the basis of a data transmission between a server and amobile client, as shown in FIG. 1.

According to FIG. 1, a mobile station 1 comprising a mobile terminal 11and a user agent 10 is radio-connected to a Base Station Subsystem (BSS)2 of a mobile network such as a GSM network. The user agent 10 may beany browser software or device that interprets content submitted from anorigin server 6 connected to the mobile station 1. Furthermore, themobile station 1 comprises a display 12 and a keyboard 13 so as toprovide a Man Machine Interface (MMI) to a user. As an example, a userof such a WAP-compliant mobile telephone requests content using aspecific URL input by using the keyboard 13. The received contentrelating to the specific URL is then displayed at the display 12.

Furthermore, the mobile network comprises a Mobile Switching Center(MSC) 3 arranged for performing all switching functions for mobilestations located in a geographical area designated as an MSC area. TheMSC 3 takes into account the impact of the allocation of radio resourcesand the mobile nature of the subscribers and has to perform, forexample, procedures required for the location registration andprocedures required for hand-over of respective mobile stations. The MSC3 is connected to the BSS 2, which is a sub-system of base stationequipment, such as transceivers, controllers, and the like, viewed bythe MSC 3 through a single interface.

The MSC 3 is connected to a gateway 5 (e.g. a WAP gateway) whichcomprises a functionality responsible for encoding and decoding datatransferred from and to a mobile client, such as the mobile station 1.The purpose of encoding content delivered to the client is to minimizethe size of data sent to the client over-the-air as well as to minimizethe computational energy required by the client to process said data.The gateway 5 provides a connection to an origin server 6 of a fixednetwork such as the Internet or another IN (Intelligent Network). Theorigin server 6 responds to a content request from a user agent with therequested data expressed in one of the standard formats known to theuser agent, e.g. HTML.

Thus, content data may be transmitted from the origin server 6 via thegateway 5, the MSC 3 and the BSS 2 to the mobile station 1 by using acircuit-switched data bearer (CSD bearer).

In addition thereto, a USSD node (USSD center) 4 connected to the MSC 3and the gateway 5 is provided in the mobile network. The USSD node 4enables a communication of data messages, i.e. unstructured data,between the mobile station 1 and the origin server 6 via the gateway 5.In particular, there may be two ways of connecting the USSD node 4 tothe mobile network.

First, the USSD node may be connected to the MSC 3 via a Home LocationRegister (HLR) 8 which is a data base in charge of the management ofmobile subscribers. All subscription data are stored there, such as anInternational Mobile Subscriber Identity (IMSI) and a locationinformation (VLR number) of each MS in order to be able to route callsto the mobile subscribers managed by the HLR 8. A mobile initiated USSDmessage is then routed to the HLR 8 via an additional Visitor LocationRegister (VLR) 7 used for controlling MSs roaming in the MSC area of theMSC 3. The VLR 7 is a data base containing information needed to handlethe calls set up or received by the MSs registered therein. Thus, theUSSD message takes the following path: MS 1→BSS 2→MSC 3→VLR 7→HLR 8→USSDnode 4→gateway 5. A network initiated USSD message takes the oppositepath.

Second, the USSD node 4 may be connected to the GSM network directly viathe MSC 3. However, in this case, only a mobile initiated USSD ispossible. The USSD message is then routed via the following path: MS1→BSS 2→MSC 3→USSD node 4→gateway 5.

Thus, a USSD bearer can be used as a transparent pipe through the GSMnetwork. In particular, the USSD bearer can be used by operators toprovide operator-specific services using a similar transport mechanismas when standard GSM supplementary services are used.

The protocol designed to hide the complexity of the USSD dialogue is theUSSD Dialogue Control Protocol (UDCP). UDCP is mapped directly onto theUSSD Protocol. The UDCP protocol layer is located in the USSD node 4. Aservice code identifies the USSD node 4 and is an operator-specificparameter, just like the address of an SMS-center. The user has tomanually enter the service code when invoking a service, or it could beentered once as a “setting” in an application (e.g. phone directory) inthe MS 1. The service code is sent in the USSD string based on apredefined format defined in the GSM specifications. Thus, the HLR 8 (orthe MSC 3 depending on the selected routing path) identifies, based onthe service code, the right USSD node 4 towards which a USSD dialogue isto be established. The USSD message is routed to the HLR 8 based on thesubscriber's IMSI.

In case of a content request from the origin server 6, the gateway 5 canbe connected to the USSD node 4. In this case, the address of thegateway 5 must be included in the USSD string. In particular, theaddress field must contain an address type (e.g. IP-address, MSISDN,etc.) and the address itself. An address field for this purpose isincluded in the UDCP protocol header.

Instead of using a specific address for the gateway 5, the service codeto the USSD node 4 can be mapped to a specific external node. In thiscase, the address field in the UDCP protocol header is omitted. Forexample, a network operator can decide that all USSD dialoguesestablished with a specific service code should be associated with thegateway 5.

In a similar manner, a GSM short message (SMS) can be used to provide anadditional data bearer to the gateway 5 in order to access the originserver 6. In GSM SMS, the user data field may comprise just the shortmessage itself or a header in addition to the short message. In thiscase, the data message is routed via a respective SMS center (which maybe the MSC 3 or another network node of the GSM network) to the gateway5.

According to the preferred embodiment of the present invention, when auser activates the user agent 10 by using the keyboard 13, the useragent 10 starts a set-up of a circuit-switched data bearer towards thegateway 5. Simultaneously or in parallel thereto, the user agent 10starts or initiates a content retrieval using a USSD or an SMS bearer.Thereby, content data can be transmitted from the origin server 6 to themobile station 1 by using the SMS or USSD bearer, while thecircuit-switched data bearer is being set-up. When the gateway 5 getsinformed either by a data call access server (not shown) or the mobilestation 1 that the CSD bearer set-up is completed, the gateway 5dynamically changes the data bearer and starts using the CSD bearer fortransmitting the remaining content requested by the user agent 10.

The data call access server is located at the gateway 5 and arranged toprovide an IP connection to the gateway 5. It is noted that the accessserver may as well be integrated into the gateway 5. The address number(e.g. IN number) of the access server can be determined in the GSMnetwork by a corresponding IN number translation. In this case, the useris provided with a universal number which can be translated to thenumber of the access server or the gateway 5. This number translationmay be performed by a CAMEL functionality of the GSM network.

FIG. 2 shows a basic block diagram of a data transmission apparatusaccording to the preferred embodiment, implemented in the gateway 5. InFIG. 2, only those parts of the gateway 5 are shown which are requiredfor implementing the present invention. According to FIG. 2, the gateway5 comprises a transceiver (TRX) unit 51 arranged for establishing and/orswitching connections between the GSM network and a fixed IN network,e.g. the Internet. In particular, the TRX unit 51 comprises a firstinput terminal connected to the USSD node 4 in order to establish a USSDconnection from the USSD node 4 towards the origin server 6.Furthermore, the TRX unit 51 comprises a second input terminal connectedto the MSC 3 via the access server for establishing a TCP/IP(Transmission Control Protocol/Internet Protocol) connection from theaccess server towards the origin server 6, wherein the access server isthen connected to the MSC 3 via a CSD connection. The switching functionof the TRX unit 51 is controlled by a bearer switching control unit 55which performs switching control so as to switch between the USSD bearerand the CSD bearer in the connection to the MS 1.

The bearer switching control unit 55 is connected to a detector 54 whichis arranged to detect the completion of a set-up phase of the CSD bearerof the CSD connection. To achieve this, the detector 54 may be connectedto the second input terminal connecting the CSD connection, or to anyother suitable terminal of the gateway 5. The detector 54 may determinethe set-up completion either by an information obtained from the accessserver or by an information obtained from the mobile station 1.

Furthermore, the gateway 5 comprises a transcoder 52 connected betweenthe TRX unit 51 and the output terminal, and arranged for encoding anddecoding data transferred from and to a mobile client. The transcoder 52is connected to a memory 53 in order to provide a buffer function forthe content delivered by the origin server 6.

In the following, a data transmission (e.g. downloading) from the originserver 6 to the mobile station 1 is described on the basis of a messagetransmission diagram comprising two examples shown in the upper andlower part of FIG. 3, respectively.

According to the upper first example, when a user of the mobile station1 activates the browser function of the user agent 10 by the keyboard 13or another suitable input means, the user agent 10 of the mobile station1 issues a CSD bearer set-up request via the MSC 3 to the access serverwhich provides an IP connection to the gateway 5.

Simultaneously, the user agent 10 starts content retrieval using a USSDbearer. In particular, the user agent 10 transmits data by issuing aUDCP data request primitive either via the MSC 3 directly or via the MSC3 and the HLR 8 to the USSD node 4. The address of the gateway 5 may beincluded in the service code of the USSD dialogue, or an additionaladdress may be used to address the origin server 6. Once the dialoguehas been established, the USSD node 4 functions as a relay and passesdata between the mobile station 1 and the gateway 5. Thus, the useragent 10 of the mobile station 1 can use the USSD bearer to communicatewith the gateway 5 identified by the service code.

Having received the USSD request, the TRX unit 51 of the gateway 5issues a content request included in the USSD message to the originserver 6 specified by the respective URL. A content generator of theorigin server 6 generates standard content formats in response to therequest from the user agent 10 of the mobile terminal 1, and transmitsthe content to the gateway 5. The content is encoded at the transcoder52 and transmitted by the TRX unit 51 as a USSD message to the USSD node4, which forwards the content (USSD message) via the established USSDpath to the MS 1.

When the gateway 5 gets informed either by the access server or themobile station 1 that the requested CSD bearer set-up is completed, thedetector 54 detects the completion, and issues a corresponding detectionresult to the bearer switching control unit 55. Then, the bearerswitching control unit 55 controls the TRX unit 51 so as to change orswitch to the TCP/IP and CSD connection using the CSD bearer between theaccess server and the mobile station 1. Then, the remaining contententities, eg. WAP decks, received from the origin server 6 or stored inthe memory 53 are downloaded via the access server, i.e. by using theCSD bearer.

Thus, the content is initially downloaded by using the quicklyestablished USSD bearer and the changing to the CSD bearer having thehigher capacity when the set-up of the CSD bearer has been confirmed.Thereby, a fast data transmission between the origin server 6 and themobile station 1 can be ensured.

According the alternative second example shown in the lower part of FIG.3, it is also possible that the gateway 5 establishes a networkinitiated USSD session via the HLR 8 and the MSC 3, when there is not somuch content to be retrieved.

In particular, an initial CSD bearer set-up request is issued by themobile station 1. In response to the receipt of a subsequent bearerestablishment confirmation, the mobile station 1 sends a content requestvia the CSD bearer to the access server which generates a correspondingIP content request transferred via the gateway 5 to the origin server 6.In response thereto, the origin server 6 sends the requested contentinformation via the gateway 5 and the access server to the mobilestation, using the CSD bearer between the access server and the mobilestation 1. When the detector 54 of the gateway 5 detects or determines apredetermined bearer need condition requiring a change to a bearer witha narrower bandwidth, it controls the bearer switch control unit 55 soas to establish a USSD session towards the MS 1, and transmits theremaining content information, received from the origin server 6, viathe USSD bearer to the MS 1.

The predetermined bearer need condition may be determined on the basisof the URL of the content, the content size, the content type (i.e.amount of data) or a passivity timer included in the detector 54 andarranged to count a time duration since the last content request.Thereby, a bearer change to the USSD bearer can be initiated in case acontent with a small amount of data (i.e. small size) is to beretrieved. If the bearer need determination is directly based on thecontent size, a preliminary indication of the content size is needed tothe gateway 5 from the origin server 6. Alternatively, the contentinformation may as well be stored in the gateway 5.

The bearer change may be performed by the gateway 5 (e.g. bearer switchcontrol unit 55) by transmitting a release request to the access serverin order to release the CSD bearer. Then the session is suspended. Whenthe release of the CSD bearer has been acknowledged from the mobilestation 1 via the access server, the gateway 5 starts a session resumeoperation and waits for a content request via an USSD bearer from themobile station 1. When the content request has been received by thegateway 5, a new content request is issued to the origin server 6. Inresponse thereto, the origin server 6 supplies the requested content tothe gateway 5 from which it is send to the mobile station 1 by using thenarrow band USSD bearer. Thereby, network capacity can be saved.

Thus, the bearer switching control unit 55 can be arranged to performcontrol such that the CSD bearer is changed back to the USSD bearerbased on the bearer need determination of the detector 54, e.g. if thereis not very much content to be downloaded.

It is noted that the bearer release may as well be initiated by themobile station 1 based on a corresponding determination operation.

If the mobile station 1 or the gateway 5 (e.g. detector 54) determine onthe basis of the URL, an anticipated content size, or a contentretrievel request that the CSD bearer must be re-established, the mobilestation 1 or the gateway 5 (e.g. bearer switch control unit 55) mayagain request a CSD bearer set-up.

The above preferred embodiment can be extended by providing a mechanismin the wireless transport protocol (e.g. WAP) to use multiple bearers inparallel. In this case, the TRX unit 51 may switch multiple bearers tothe origin server 6. Thereby, unsent content entities can be swapped tothe CSD bearer even during the downloading of a specific content entityusing the USSD bearer.

It is to be noted that the initial or narrow band content transmissionmay as well be performed by an SMS bearer via a corresponding SMScenter, eg. the MSC 3, of the GSM network. In this case, the TRX unit 51connects to the SMS center and uses the SMS bearer in response to thecontrol of the bearer switching control unit 55. Moreover, any otherdata transmission bearer which can be established in a short durationcan be used as the initial data bearer.

As an alternative example, the user agent 10 may start a WAP session andinitiate a datacall (CSD bearer) to an IN number. The MSC 3 routes thedatacall to the access server connected to the WAP gateway 5 based on anumber conversion performed by the IN. Then, the IN may inform thegateway 5 to start a network initiated WAP over USSD (or SMS) sessione.g. through an http interface. The gateway 5 may check whether themobile station 1 supports WAP over USSD or WAP over SMS using acorresponding database provided in the gateway 5 or any other networkelement (eg. Home Location Register (HLR) or Visitor Location Register(VLR)). When it has been detected by the detector 54 that the set-up ofthe CSD bearer of the data call is complete, the bearer switchingcontrol unit 55 controls the TRX unit 51 so as to change the bearerdynamically from the USSD or SMS bearer to the CSD bearer.

Whether the mobile station 1 supports WAP over USSD may also be checkedby pinging the mobile station 1, wherein the gateway 5 pings the mobilestation 1 with a WCMP (Wireless Control Message Protocol) Echo Request(over USSD). Then, the mobile station 1 may answer with a WCMP EchoReply, if it supports WAP over USSD. In this case, WAP over USSD can beused. If the mobile station 1 does not support WAP over USSD, it answerswith an error message.

In general, the switching between the USSD or SMS bearer and the CSDbearer can be implemented or extended by using a WAP session suspend andresume operation which allow the use of a given session to betemporarily frozen. When the USSD or SMS bearer is to be changed to theCSD bearer, the session is suspended via the USSD or SMS bearer, andthen resumed via the CSD bearer.

According to a third example of the preferred embodiment, the bearerchange may be used by the gateway 5 to obtain charging data for acontent retrieval. This can be achieved by gathering the charging dataper MSISDN, since the user MSISDN is supplied to the gateway 5 when aUSSD or SMS bearer is used. The MSISDN obtained by the gateway 5 fromthe USSD node 4 or the SMS center is reliable, since the mobile station1 has been authenticated using the GSM authentication mechanism and theGSM network is closed and controlled by the operator all the way fromthe base transceiver station of the BSS 2 to the USSD node 4 or the SMScenter.

The charging data gathered at the gateway 5 may comprise a userinformation (e.g. MSISDN), the content retrieved (URL) and a contentretrieval time. Of course, the gateway 5 may as well forward this datato an operator billing system.

FIG. 4 shows message transmission diagram of a data transmission (e.g.downloading) from the origin server 6 to the mobile station 1, accordingto the third example. Initially, a USSD content request is transmittedfrom the mobile station 1 to the gateway 5 via the USSD node 4. Thegateway 5 (e.g. detector 54) detects the respective MSISDN of the mobilestation 1 and issues a corresponding content request to the originserver 6 which then generates a content information and supplies it tothe gateway 5. The gateway 5 transmits the content information via theUSSD node 4 to the mobile station 1 by using a USSD bearer. Then, themobile station 1 initiates a bearer release message, e.g. a WSP SessionSuspend message or the like, by using the initial USSD bearer. Inresponse thereto, the gateway 5 issues a session suspend command(suspend PDU) to the origin server 6 which acknowledges the suspension.Then, the gateway 5 transmits a corresponding acknowledgement via theUSSD bearer to the mobile station 1 and the bearer switch control unit55 initiates a release of the USSD bearer.

Having received the suspension acknowledgement, the mobile station 1initiates a CSD bearer set-up and issues a session resume request, e.g.a WSP Session Resume message or the like, to the gateway 5 by using theCSD bearer after it has been set up. Alternatively, the CSD bearerset-up may be initiated in parallel with the start of the initialtransmission using the USSD bearer, to thereby speed up thecommunication. After the session resumption has been acknowledged by theorigin server 6, the content retrieval is continued by using the CSDbearer.

Due to the combined use of the USSD bearer and the CSD bearer, bothMSISDN and IP addresses are known to the gateway 5 which may thenassociate the MSISDN with the IP address to thereby gather billing orcharging data per service. The charging data which may comprise the useror subscriber identity (MSISDN), the content retrieved (URL) and/or acontent retrieval time may be gathered by the switch control unit 55.Then, the charging data may be forwarded to an operator billing orcharging system.

It is noted that the blocks 51, 52, 54 and 55 shown in FIG. 2 may beimplemented as hardware circuits or as software routines executed by acorresponding processing unit arranged at the gateway 5. As alreadymentioned, the gateway function may be provided at the origin server 6.In this case, the USSD node 4 and the MSC 3 may be directly connected tothe origin server 6. Furthermore, the data transmission method andapparatus described in the preferred embodiment can be applied to anydata transmission between end terminals of a telecommunication network,wherein the term “end terminal” is intended to cover also arbitrarynetwork nodes, e.g. any network node from which a content can beretrieved. Moreover, the second bearer is not restricted to a CSDbearer. Other bearer types, such as a GPRS bearer, may be used insteadof the CSD bearer. The above description of the preferred embodiment andthe accompanying drawings are only intended to illustrate the presentinvention. The preferred embodiment of the invention may thus varywithin the scope of the attached claims.

In summary, the present invention relates to a data transmission methodand apparatus for performing a data transmission between end terminalsof a telecommunication network, particularly a data transmission betweenan origin server and a mobile client. The data is transmitted from atleast one of the end terminals using the first data bearer. Then, datatransmission is switched from the first to the second data bearer, if apredetermined bearer need condition has been determined or in order toobtain a subscriber identity used for gathering charging data. Thereby,the network service provided by the operator can be improved, since thebearer switching allows an increase of the overall speed of the datatransmission, an adaptation of the bearer bandwidth to the data amount,and a provision of the subscriber identity. The first data bearer may bea USSD or SMS data bearer, and the second data bearer may be acircuit-switched data bearer or a GPRS bearer, or vice versa.

1. A method comprising: initiating data transmission from an intelligentnetwork access server to a mobile station using a first data bearer of afirst type for transmitting data upon request for communication with theaccess server by the mobile station; receiving content by the accessserver from an origin server upon request for content by the mobilestation and transmitting said content to the mobile station on the firstdata bearer of a first type; switching said data transmission to asecond data bearer of a second type different from said first type, saidsecond data bearer having a different set-up phase than the first databearer, when said set-up phase of the second data bearer is completedand when a predetermined bearer need condition of said second databearer has been determined, said predetermined bearer need conditionbeing associated with the amount of data to be transmitted from theorigin server to the mobile station as a result of said request forcontent, and continuing said data transmission on said second databearer of a second type, wherein said data transmission delivers thecontent from the origin server to the mobile station, and determining anaddress number of said intelligent network access server by anintelligent network number translation, wherein said intelligent networknumber translation is determined by customized applications for mobilenetwork enhanced logic support.
 2. A method comprising: initiating datatransmission from an intelligent network access server to a mobilestation using a first data bearer of a first type for transmitting data;receiving content by the access server from an origin server uponrequest for communication with the access server by the mobile stationand transmitting said content to the mobile station on the first databearer of a first type; switching said data transmission to a seconddata bearer of a second type different from said first type said seconddata bearer having a different set-up phase than the first data bearer,when said set-up phase of the second data bearer is completed and when apredetermined bearer need condition of said second data bearer has beendetermined, said predetermined bearer need condition being associatedwith the amount of data to be transmitted from the origin server to themobile station, wherein said data transmission is used for retrievingsaid requested content from said origin server, and determining anaddress number of said intelligent network access server by anintelligent network number translation, and wherein said intelligentnetwork access server is arranged in a wireless application protocolgateway.
 3. A method comprising: initiating data transmission from anaccess server to a mobile station using a first data bearer of a firsttype for transmitting data upon request for communication with theaccess server by the mobile station; receiving content by the accessserver from an origin server upon request for content by the mobilestation and transmitting said content to the mobile station on the firstdata bearer of a first type; switching said data transmission to asecond data bearer of a second type different from said first type, saidsecond data bearer having a different set-up phase than the first databearer, when said set-up phase of the second data bearer is completedand when a predetermined bearer need condition of said second databearer has been determined, said predetermined bearer need conditionbeing associated with the amount of data to be transmitted from theorigin server to the mobile station as a result of said request forcontent, and continuing said data transmission on said second databearer of a second type, wherein said data transmission delivers thecontent from the origin server to the mobile station, and wherein saidswitching is performed during downloading of said requested contentusing said first data bearer, so that remaining content of saidrequested content is downloaded using said second data bearer.
 4. Amethod according to claim 3, wherein said predetermined bearer needcondition is the completion of the set-up phase of said second bearer.5. A method according to claim 4, wherein said first data bearer is anunstructured supplementary service data or short message service bearer,and said second data bearer is a circuit-switched data bearer.
 6. Amethod according to claim 3, wherein the amount of data is determinedfrom at least one of the following: a service address, a content sizeand a content type of a service information to be transmitted.
 7. Amethod according to claim 3, wherein said predetermined bearer needcondition is determined on the basis of a time duration since a lasttransmission request.
 8. A method according to claim 3 wherein saidfirst data bearer is a circuit-switched data bearer, and said seconddata bearer is a unstructured supplementary service data or shortmessage service bearer.
 9. A method according to claim 3, wherein saidswitching comprises a wireless application protocol session suspend andresume operation.
 10. A method according to claim 9, wherein thewireless application protocol session is suspended via said first databearer and resumed via said second data bearer.
 11. An apparatuscomprising: a bearer control switch configured to control a transmitterfor initiating a data transmission from an access server to a mobilestation using a first data bearer of a first type for transmitting data;and a detector configured to detect a predetermined bearer needcondition; wherein said bearer control switch is configured to switchsaid transmitter to a second data bearer of a second type different fromsaid first type, said second data bearer having a different set-up phasethan the first data bearer, based on completion of the set-up phase ofthe second data bearer and based on the detected predetermined bearerneed condition, and configured to control said transmitter to continuethe data transmission from said access server to said mobile station onthe second data bearer, wherein said predetermined bearer need conditionis associated with the amount of data to be transmitted from an originserver to the mobile station via the access server as a result of arequest for content from the mobile station to the access server.
 12. Anapparatus according to claim 11, wherein said predetermined bearer needcondition is the completion of the set-up phase of said second bearer.13. An apparatus according to claim 12, wherein said first data beareris an unstructured supplementary service data or short message servicebearer, and said second data bearer is a circuit-switched data bearer.14. An apparatus according to claim 11, wherein an amount of data isdetermined from at least one of the following: a service address, acontent size and a content type of a service information to betransmitted.
 15. An apparatus according to claim 11, wherein saidpredetermined bearer need condition is determined on the basis of a timeduration since a last transmission request.
 16. An apparatus accordingto claim 11, wherein said first data bearer is a circuit-switched databearer, and said second data bearer is an unstructured supplementaryservice data or short message service bearer.
 17. An apparatus accordingto claim 11, wherein said apparatus is provided in a wirelessapplication protocol gateway, and wherein said bearer control switch isconfigured to perform said switching by using a wireless applicationprotocol session suspend and resume operation.
 18. An apparatuscomprising: a bearer control switch configured to control a transmitterfor initiating a data transmission from an access server to a mobilestation using a first data bearer of a first type to transmit data froman origin server to the mobile station via the access server, whereinsaid initiating includes actual transmission of data from the accessserver using said first data bearer; and a detector configured to detecta predetermined bearer need condition, wherein said bearer controlswitch is configured to switch said transmitter to a second data bearerof a second type different from said first type, said second data bearerhaving a different set-up phase than the first data bearer, based oncompletion of the set-up phase of the second data bearer and based onthe detected predetermined bearer need condition, and configured tocontrol said transmitter to continue the data transmission on the seconddata bearer of a second type from said access server to said mobilestation, wherein said predetermined bearer need condition is associatedwith the amount of data to be transmitted as a result of a request forcontent.
 19. An apparatus according to claim 18, wherein said first databearer is an unstructured supplementary service data or short messageservice bearer, and a second data bearer is a circuit-switched databearer or a general packet radio service bearer.
 20. An apparatusaccording to claim 18, wherein said apparatus is provided in a wirelessapplication protocol gateway, and wherein said bearer control switch isconfigured to perform said switching by using a wireless applicationprotocol session suspend and resume operation.
 21. An apparatusaccording to claim 18, wherein said predetermined bearer need conditionis the completion of the set-up phase of said second data bearer.
 22. Anapparatus according to claim 18, wherein said predetermined bearer needcondition is determined on the basis of a time duration since a lasttransmission request.
 23. An apparatus according to claim 18, whereinsaid data transmitted by said access server is received from an originserver.
 24. An apparatus according to claim 23 wherein said bearercontrol switch is configured to control said transmitter so as to switchto said second data bearer during a downloading of said requestedcontent from said origin server to said mobile station using said firstdata bearer, so that remaining content of said requested content isswapped to said second data bearer.
 25. An apparatus according to claim18, wherein the detector is configured to detect a subscriber identityfrom the data transmission with said first data bearer, wherein saidbearer control switch is configured to gather subscriber charging databy using said detected subscriber identity, and wherein said subscriberidentity is a mobile station integrated services digital network.
 26. Aterminal equipment for a telecommunication network, comprising: an inputdevice configured to activate a browser function; and a user agentresponsive via the browser function to said input device, configured torequest content retrieval from an origin server via an access server byusing a first data bearer of a first type for transmitting data and asecond data bearer of a second type different from said first type fortransmitting data, said second data bearer having a different set-upphase than the first data bearer, wherein said content retrievalincludes actual data and is performed by using said first data bearerduring set-up of the second data bearer and switching to said seconddata bearer after said set-up of the second data bearer and upondetection of a predetermined bearer need condition, said predeterminedbearer need condition being associated with the amount of data to betransmitted as a result of said requested content retrieval.
 27. Aterminal equipment according to claim 26, wherein said first data beareris an unstructured supplementary service data or short message servicedata bearer, and said second data bearer is a circuit-switched databearer or a general packet radio service bearer.
 28. A terminalequipment according to claim 26, wherein said terminal equipment isprovided in a mobile station.
 29. An apparatus comprising: means forcontrolling a transmitter for initiating a data transmission from anaccess server to a mobile station using a first data bearer of a firsttype for transmitting data upon request for communication with theaccess server by the mobile station; and means for detecting apredetermined bearer need condition; wherein said means for controllingcontrols said transmitter so as to switch to a second data bearer of asecond type different from said first type, said second data bearerhaving a different set-up phase than the first data bearer, based oncompletion of the set-up phase of the second data bearer and based onthe detected predetermined bearer need condition, and configured tocontrol said transmitter to continue the data transmission from saidaccess server to said mobile station on the second data bearer, whereinsaid predetermined bearer need condition is associated with the amountof data to be transmitted as a result of said request for content,wherein said data transmitted by said access server is received from anorigin server, and wherein said means for controlling switches saidtransmitter to said second data bearer during a downloading of saidrequested content from said origin server to said mobile station usingsaid first data bearer, so that remaining content of said requestedcontent is downloaded using said second data bearer.
 30. An apparatusaccording to claim 29, wherein said predetermined bearer need conditionis the completion of the set-up phase of said second bearer.
 31. Amethod comprising: initiating data transmission from an access server toa mobile station using a first data bearer of a first type fortransmitting data upon request for communication with the access serverby the mobile station; receiving content by the access server from anorigin server upon request for content by the mobile station andtransmitting said content to the mobile station on the first data bearerof a first type; switching said data transmission to a second databearer of a second type different from said first type, said second databearer having a different set-up phase than the first data bearer, whensaid set-up phase of the second data bearer is completed and when apredetermined bearer need condition of said second data bearer has beendetermined, said predetermined bearer need condition being associatedwith the amount of data to be transmitted from the origin server to themobile station as a result of said request for content.
 32. A methodaccording to claim 31, wherein said predetermined bearer need conditionis the completion of the set-up phase of said second data bearer.
 33. Amethod according to claim 31, wherein said predetermined bearer needcondition is determined on the basis of a time duration since a lasttransmission request.
 34. A method according to claim 31, furthercomprising using a subscriber identity, obtained from the datatransmission with said first data bearer, for gathering subscribercharging data, wherein said subscriber identity is a mobile stationintegrated service digital network.